1. Gross neuroanatomy measures & introduction to variability References Steinmetz H., Furst, G., Freund, H., “Cerebral Cortical Localization: application and validation of the proportional grid system in MR Imaging”, 1989, Journal of Computer Assisted Tomography, 13(1):10-19 Ono M., Kubik S., Abernathey C.D., Atlas of the cerebral sulci, 1990, Thieme Verlag

2. Talairach transformation & variability range of main sulci

3. Method Tomographic images are collected on 30 hemispheres of 15 people (22-63 yo) Talairach transformation is performed using 4 AC PC and 5 extreme landmarks Sulci are identified manually and projected sagitally Align extreme points Shift AC PC vertically and side-to-side AC PC AC PC

4. Central Sulcus 20 hemispheres Sylvian Fissure (R) 15 hemispheres Sylvian Fissure (L) 15 hemispheres Calossal, Parietooccipital, Marginal sulci, 30 hemispheres Leftover variability after Talairach transformation

5. Summary Central sulcus (CS) in the postmortem Talairach brain is located 0.5- 1.0 cm anterior to the CS in the 30 hemispheres studied here 2-3 cm displacement is observed in most of the studied major sulci

6. Incidence rates of main sulci

7. Method 25 postmortem brains Length determined by running a chord inside sulci Molded silicon models are developed to study internals of the sulci

8. Statistics